Impact of positive surgical margins on biochemical relapse after radical retropubic prostatectomy (RRP)

RP (radical prostatectomy) technique continues the major treatment option for men with potential cure and life expectancy exceeding 10 years. The aim of the study is to assess the impact of PSM on BR (biochemical relapse), to identify PSM risk factors, to clarify the factors involved in BR in the absence of PSM.

Consultation of 171 medical-records from patients submitted to RRP (radical retropubic prostatectomy) between January/2000-December/2005. Mean-age: 64 yr. Mean - PSA (positive surgical margin): 11.88 ng/ml. Clinical staging: 67.8% cT1, 32.2% cT2. GS: ≤6 (66.1%), =7 (21.1%), 8-10 (12.3%). PS: pT0 1.2%, pT2 50.3%, pT3a 36.3%, pT3b 12.9%, pT4 0.6%. pathological Gleason score: ≤6 39.2%, =7 40.9%, 8-10 19.3%. RB definition was PSA ≥0.2 ng/ml. Adjusted Odds-Ratios with 95% confidence intervals (CI) were estimated through univariate logistic regression.

There were PSM in 46 specimens, 28 had single PSM and 18 multiple PSM (≥2). BR occurred in 57 patients (33.3%), with an average time after surgery of 23.5 months - 26 patients had PSM and 31 had not. Statistical significant results for BR in variables PSA, PS and PSM. Quadruples if PSM (p <0.0001), triples in single PSM (p = 0.01) and is 6x higher in multiple PSM (p = 0.001). Regarding factors that influence the presence of PSM, only PS ≥pT3a reach statistical significance (p <0.0001). Patients with BR but without PSM (54.38%), variables statistically significant were: initial PSA >10, (p = 0.029) and pathological Gleason score ≥8 with a risk nearly 4x higher than pathological Gleason score ≤6 (p = 0.027).

Statistical risk analysis concluded that the presence of PSM in RRP is strongly influenced by PS ≥pT3a. The presence of PSM and their number increase significantly the risk of BR compared to other factors. In the absence of PSM, the factors that seem to be crucial and with greater impact on BR are initial PSA>10 and pathological Gleason score ≥8.